I would say that system is reports, get your team on it and get the opponents to do them as well. Remember that if your not coming across as a flamer or toxic your way more likely to generate sympathy from your opponents and get some of those glorious 9 man reports that end up providing a "we punished a player you reported thanks for helping us remove the unsavory" messages from riot.
As for bad teammates, part of the game. My personal stance is if your good you inherently have an advantage in every single game you play because the odds of enemy team having more bad players is higher then your team. It might not happen and your gonna have streaks of losses from teammates because that's how it goes, but law of large numbers is a thing and it balances out into you climbing ladder if you just keep playing. When I started to improve (I was low bronze in season 1.) I found for me that the key is to always focus on yourself first, and try to keep everybody's attitude in a match from falling into GG thresholds of salty. I got wins this season with folks who intentionally started feeding but managed to talk them down and turn the game around. This is obviously not true for every game and wont work every time but anything that improves your win rate is a good thing in my book, cuz law of numbers. Anyhow mate bit of a long post... heh... I wish you best of luck on the rift. Good luck and have fun.